// Dear ImGui: standalone example application for DirectX 11

// Learn about Dear ImGui:
// - FAQ                  https://dearimgui.com/faq
// - Getting Started      https://dearimgui.com/getting-started
// - Documentation        https://dearimgui.com/docs (same as your local docs/
// folder).
// - Introduction, links and more at the top of imgui.cpp
//=================================================================================================
// @SAMPLE_EDIT
#include <chrono>
#include <thread>

#include "Sample.h"
//=================================================================================================

#include <d3d11.h>
#include <tchar.h>

#include "imgui.h"
#include "imgui_impl_dx11.h"
#include "imgui_impl_win32.h"

// Data
ID3D11Device* g_pd3dDevice = nullptr;  // @SAMPLE_EDIT (removed static)
static ID3D11DeviceContext* g_pd3dDeviceContext = nullptr;
static IDXGISwapChain* g_pSwapChain = nullptr;
static bool g_SwapChainOccluded = false;
static UINT g_ResizeWidth = 0, g_ResizeHeight = 0;
static ID3D11RenderTargetView* g_mainRenderTargetView = nullptr;

// Forward declarations of helper functions
bool CreateDeviceD3D(HWND hWnd);
void CleanupDeviceD3D();
void CreateRenderTarget();
void CleanupRenderTarget();
LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);

// Main code
int main(int, char**) {
  // Make process DPI aware and obtain main monitor scale
  ImGui_ImplWin32_EnableDpiAwareness();
  float main_scale = ImGui_ImplWin32_GetDpiScaleForMonitor(
      ::MonitorFromPoint(POINT{0, 0}, MONITOR_DEFAULTTOPRIMARY));

  // Create application window
  WNDCLASSEXW wc = {sizeof(wc),
                    CS_CLASSDC,
                    WndProc,
                    0L,
                    0L,
                    GetModuleHandle(nullptr),
                    nullptr,
                    nullptr,
                    nullptr,
                    nullptr,
                    L"ImGui Example",
                    nullptr};
  ::RegisterClassExW(&wc);
  HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX11 Example",
                              WS_OVERLAPPEDWINDOW, 100, 100,
                              (int)(1280 * main_scale), (int)(800 * main_scale),
                              nullptr, nullptr, wc.hInstance, nullptr);

  // Initialize Direct3D
  if (!CreateDeviceD3D(hwnd)) {
    CleanupDeviceD3D();
    ::UnregisterClassW(wc.lpszClassName, wc.hInstance);
    return 1;
  }

  // Show the window
  ::ShowWindow(hwnd, SW_SHOWDEFAULT);
  ::UpdateWindow(hwnd);

  // Setup Dear ImGui context
  IMGUI_CHECKVERSION();
  ImGui::CreateContext();
  ImGuiIO& io = ImGui::GetIO();
  (void)io;
  io.ConfigFlags |=
      ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
  io.ConfigFlags |=
      ImGuiConfigFlags_NavEnableGamepad;             // Enable Gamepad Controls
  io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;  // Enable Docking
  // io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;         // Enable
  // Multi-Viewport / Platform Windows // @SAMPLE_EDIT disabled temporarily
  // io.ConfigViewportsNoAutoMerge = true;
  // io.ConfigViewportsNoTaskBarIcon = true;
  // io.ConfigViewportsNoDefaultParent = true;
  // io.ConfigDockingAlwaysTabBar = true;
  // io.ConfigDockingTransparentPayload = true;

  // Setup Dear ImGui style
  ImGui::StyleColorsDark();
  // ImGui::StyleColorsLight();

  // Setup scaling
  ImGuiStyle& style = ImGui::GetStyle();
  style.ScaleAllSizes(
      main_scale);  // Bake a fixed style scale. (until we have a solution for
                    // dynamic style scaling, changing this requires resetting
                    // Style + calling this again)
  style.FontScaleDpi =
      main_scale;  // Set initial font scale. (using io.ConfigDpiScaleFonts=true
                   // makes this unnecessary. We leave both here for
                   // documentation purpose)
  io.ConfigDpiScaleFonts =
      true;  // [Experimental] Automatically overwrite style.FontScaleDpi in
             // Begin() when Monitor DPI changes. This will scale fonts but
             // _NOT_ scale sizes/padding for now.
  io.ConfigDpiScaleViewports =
      true;  // [Experimental] Scale Dear ImGui and Platform Windows when
             // Monitor DPI changes.

  // When viewports are enabled we tweak WindowRounding/WindowBg so platform
  // windows can look identical to regular ones.
  if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) {
    style.WindowRounding = 0.0f;
    style.Colors[ImGuiCol_WindowBg].w = 1.0f;
  }

  // Setup Platform/Renderer backends
  ImGui_ImplWin32_Init(hwnd);
  ImGui_ImplDX11_Init(g_pd3dDevice, g_pd3dDeviceContext);

  // Load Fonts
  // - If no fonts are loaded, dear imgui will use the default font. You can
  // also load multiple fonts and use ImGui::PushFont()/PopFont() to select
  // them.
  // - AddFontFromFileTTF() will return the ImFont* so you can store it if you
  // need to select the font among multiple.
  // - If the file cannot be loaded, the function will return a nullptr. Please
  // handle those errors in your application (e.g. use an assertion, or display
  // an error and quit).
  // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype
  // for higher quality font rendering.
  // - Read 'docs/FONTS.md' for more instructions and details.
  // - Remember that in C/C++ if you want to include a backslash \ in a string
  // literal you need to write a double backslash \\ !
  // style.FontSizeBase = 20.0f;
  // io.Fonts->AddFontDefault();
  // io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
  // io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
  // io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
  // io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
  // ImFont* font =
  // io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
  // IM_ASSERT(font != nullptr);

  // Our state
  bool show_demo_window = true;
  bool show_another_window = false;
  ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

  // Main loop
  bool done = false;
  Sample::Base& sample = GetSample();  // @SAMPLE_EDIT
  done = !sample.Startup();            // @SAMPLE_EDIT
  while (!done) {
    // Poll and handle messages (inputs, window resize, etc.)
    // See the WndProc() function below for our to dispatch events to the Win32
    // backend.
    MSG msg;
    while (::PeekMessage(&msg, nullptr, 0U, 0U, PM_REMOVE)) {
      ::TranslateMessage(&msg);
      ::DispatchMessage(&msg);
      if (msg.message == WM_QUIT) done = true;
    }
    if (done) break;

    // Handle window being minimized or screen locked
    if (g_SwapChainOccluded &&
        g_pSwapChain->Present(0, DXGI_PRESENT_TEST) == DXGI_STATUS_OCCLUDED) {
      ::Sleep(10);
      continue;
    }
    g_SwapChainOccluded = false;

    // Handle window resize (we don't resize directly in the WM_SIZE handler)
    if (g_ResizeWidth != 0 && g_ResizeHeight != 0) {
      CleanupRenderTarget();
      g_pSwapChain->ResizeBuffers(0, g_ResizeWidth, g_ResizeHeight,
                                  DXGI_FORMAT_UNKNOWN, 0);
      g_ResizeWidth = g_ResizeHeight = 0;
      CreateRenderTarget();
    }

    // Start the Dear ImGui frame
    ImGui_ImplDX11_NewFrame();
    ImGui_ImplWin32_NewFrame();

#if 0   // @SAMPLE_EDIT
        ImGui::NewFrame();

        // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
        if (show_demo_window)
            ImGui::ShowDemoWindow(&show_demo_window);

        // 2. Show a simple window that we create ourselves. We use a Begin/End pair to create a named window.
        {
            static float f = 0.0f;
            static int counter = 0;

            ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.

            ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
            ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
            ImGui::Checkbox("Another Window", &show_another_window);

            ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
            ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color

            if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
                counter++;
            ImGui::SameLine();
            ImGui::Text("counter = %d", counter);

            ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
            ImGui::End();
        }

        // 3. Show another simple window.
        if (show_another_window)
        {
            ImGui::Begin("Another Window", &show_another_window);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
            ImGui::Text("Hello from another window!");
            if (ImGui::Button("Close Me"))
                show_another_window = false;
            ImGui::End();
        }

        // Rendering
        ImGui::Render();
        const float clear_color_with_alpha[4] = { clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w };
        g_pd3dDeviceContext->OMSetRenderTargets(1, &g_mainRenderTargetView, nullptr);
        g_pd3dDeviceContext->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
        ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());

        // Update and Render additional Platform Windows
        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
        {
            ImGui::UpdatePlatformWindows();
            ImGui::RenderPlatformWindowsDefault();
        }
#endif  // @SAMPLE_EDIT

    //=========================================================================================
    // @SAMPLE_EDIT EDIT TO ORIGINAL IMGUI main.cpp

    IM_UNUSED(show_demo_window);
    IM_UNUSED(show_another_window);

    // Avoids high CPU/GPU usage by releasing this thread until enough time has
    // passed
    static auto sLastTime = std::chrono::steady_clock::now();
    std::chrono::duration<float> elapsedSec =
        std::chrono::steady_clock::now() - sLastTime;
    if (elapsedSec.count() < 1.f / 120.f) {
      std::this_thread::sleep_for(std::chrono::microseconds(250));
      continue;
    }

    // Draw the Local Imgui UI and remote imgui UI
    sLastTime = std::chrono::steady_clock::now();
    const float clear_color_with_alpha[4] = {
        clear_color.x * clear_color.w, clear_color.y * clear_color.w,
        clear_color.z * clear_color.w, clear_color.w};
    g_pd3dDeviceContext->OMSetRenderTargets(1, &g_mainRenderTargetView, NULL);
    g_pd3dDeviceContext->ClearRenderTargetView(g_mainRenderTargetView,
                                               clear_color_with_alpha);
    sample.Draw();
    if (ImGui::GetDrawData()) {
      ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
    }
    // Update and render additional Platform Windows
    static int sLastFrame = -1;
    int newFrame = ImGui::GetFrameCount();

    if (sLastFrame != newFrame &&
        io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) {
      sLastFrame = newFrame;
      ImGui::UpdatePlatformWindows();
      ImGui::RenderPlatformWindowsDefault();
    }
    //=========================================================================================

    // Present
    // HRESULT hr = g_pSwapChain->Present(1, 0);   // Present with vsync
    HRESULT hr = g_pSwapChain->Present(0, 0);  // Present without vsync
    g_SwapChainOccluded = (hr == DXGI_STATUS_OCCLUDED);
  }

  // Cleanup
  ImGui_ImplDX11_Shutdown();
  ImGui_ImplWin32_Shutdown();
  sample.Shutdown();  // @SAMPLE_EDIT
  ImGui::DestroyContext();

  CleanupDeviceD3D();
  ::DestroyWindow(hwnd);
  ::UnregisterClassW(wc.lpszClassName, wc.hInstance);

  return 0;
}

// Helper functions
bool CreateDeviceD3D(HWND hWnd) {
  // Setup swap chain
  DXGI_SWAP_CHAIN_DESC sd;
  ZeroMemory(&sd, sizeof(sd));
  sd.BufferCount = 2;
  sd.BufferDesc.Width = 0;
  sd.BufferDesc.Height = 0;
  sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
  sd.BufferDesc.RefreshRate.Numerator = 60;
  sd.BufferDesc.RefreshRate.Denominator = 1;
  sd.Flags = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;
  sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
  sd.OutputWindow = hWnd;
  sd.SampleDesc.Count = 1;
  sd.SampleDesc.Quality = 0;
  sd.Windowed = TRUE;
  sd.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;

  UINT createDeviceFlags = 0;
  // createDeviceFlags |= D3D11_CREATE_DEVICE_DEBUG;
  D3D_FEATURE_LEVEL featureLevel;
  const D3D_FEATURE_LEVEL featureLevelArray[2] = {
      D3D_FEATURE_LEVEL_11_0,
      D3D_FEATURE_LEVEL_10_0,
  };
  HRESULT res = D3D11CreateDeviceAndSwapChain(
      nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, createDeviceFlags,
      featureLevelArray, 2, D3D11_SDK_VERSION, &sd, &g_pSwapChain,
      &g_pd3dDevice, &featureLevel, &g_pd3dDeviceContext);
  if (res == DXGI_ERROR_UNSUPPORTED)  // Try high-performance WARP software
                                      // driver if hardware is not available.
    res = D3D11CreateDeviceAndSwapChain(
        nullptr, D3D_DRIVER_TYPE_WARP, nullptr, createDeviceFlags,
        featureLevelArray, 2, D3D11_SDK_VERSION, &sd, &g_pSwapChain,
        &g_pd3dDevice, &featureLevel, &g_pd3dDeviceContext);
  if (res != S_OK) return false;

  CreateRenderTarget();
  return true;
}

void CleanupDeviceD3D() {
  CleanupRenderTarget();
  if (g_pSwapChain) {
    g_pSwapChain->Release();
    g_pSwapChain = nullptr;
  }
  if (g_pd3dDeviceContext) {
    g_pd3dDeviceContext->Release();
    g_pd3dDeviceContext = nullptr;
  }
  if (g_pd3dDevice) {
    g_pd3dDevice->Release();
    g_pd3dDevice = nullptr;
  }
}

void CreateRenderTarget() {
  ID3D11Texture2D* pBackBuffer;
  g_pSwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer));
  g_pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr,
                                       &g_mainRenderTargetView);
  pBackBuffer->Release();
}

void CleanupRenderTarget() {
  if (g_mainRenderTargetView) {
    g_mainRenderTargetView->Release();
    g_mainRenderTargetView = nullptr;
  }
}

// Forward declare message handler from imgui_impl_win32.cpp
extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd,
                                                             UINT msg,
                                                             WPARAM wParam,
                                                             LPARAM lParam);

// Win32 message handler
// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if
// dear imgui wants to use your inputs.
// - When io.WantCaptureMouse is true, do not dispatch mouse input data to your
// main application, or clear/overwrite your copy of the mouse data.
// - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to
// your main application, or clear/overwrite your copy of the keyboard data.
// Generally you may always pass all inputs to dear imgui, and hide them from
// your application based on those two flags.
LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) {
  if (ImGui_ImplWin32_WndProcHandler(hWnd, msg, wParam, lParam)) return true;

  switch (msg) {
    case WM_SIZE:
      if (wParam == SIZE_MINIMIZED) return 0;
      g_ResizeWidth = (UINT)LOWORD(lParam);  // Queue resize
      g_ResizeHeight = (UINT)HIWORD(lParam);
      return 0;
    case WM_SYSCOMMAND:
      if ((wParam & 0xfff0) == SC_KEYMENU)  // Disable ALT application menu
        return 0;
      break;
    case WM_DESTROY:
      ::PostQuitMessage(0);
      return 0;
  }
  return ::DefWindowProcW(hWnd, msg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine, int nShowCmd) {
  IM_UNUSED(hInstance);
  IM_UNUSED(hPrevInstance);
  IM_UNUSED(lpCmdLine);
  IM_UNUSED(nShowCmd);
  return main(0, nullptr);
}
//=================================================================================================